ci: add file hygiene workflow and canonical config templates
Add caller workflow for the reusable lint-files.yml from the .github repo, along with canonical .gitattributes, .editorconfig, and .markdownlint.yml. Replace existing .yamllint.yml with canonical version. Enables automated checks for BOM, CRLF, trailing whitespace, shell script issues, markdown formatting, and YAML validity on every PR. Refs: hyperledger-identus/hyperledger-identus#172 Signed-off-by: Yurii Shynbuiev <[email protected]> Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]> Signed-off-by: Yurii Shynbuiev <[email protected]>